1. Field of the Invention
The present invention relates to a gas valve with electromagnetic actuation, in particular to a fuel injection valve for gas engines, which includes a sealing element, actuable by way of an armature of a controllable electromagnet, between a or each fuel inlet and a or each fuel outlet, and at least one closing spring acting on the sealing element.
2. The Prior Art
In conventional gas engines based on the Otto principle, the fuel gas is admixed in the intake port and then supplied to the cylinders. Control valves and static mixers, for example, are used in this procedure. However, these systems are too unwieldy for systems with electronic fuel injection. Gas nozzles switched by way of magnets have therefore been used, these nozzles metering the fuel and producing a combustible mixture in the entire supply system. On account of the fact that the passage cross-sections are too small in conventional gas valves for use in commercial vehicles, it is necessary to bundle these gas valves, typically up to twelve of them, to obtain sufficient cross-sections (corresponding to the central injection which is customary in passenger vehicles). For this reason, gas engines, for example CNG (compressed natural gas), LPG (liquefied petroleum gas) or hydrogen engines, should also only be operated at present without supercharging, that is to say at atmospheric pressure, and typically achieve about 145 kW. However, for improved controllability, better fuel utilization and more favorable pollutant emissions, preference is given to systems which operate with so-called sequential fuel injection (also known as multi-point injection or ported-gas admission) and supply each cylinder individually with its combustible mixture by way of separate injectors or valves. In this case, it is not necessary for a combustible mixture to be present in the entire intake system, and the fuel injection mainly takes place during the intake cycle of the respective cylinder only. However, the valves known at present are unsuitable for use in such systems, since their passage cross-sections of not more than 4 to 5 mm.sup.2 are too small, so that, per cylinder, two valves would be needed in atmospheric engines and three valves in supercharged engines. However, this is scarcely possible for structural reasons. On the other hand, the requirement for a larger passage cross-section entails ever-greater difficulties as regards obtaining the required short switching times and the high metering precision necessary, resulting in a low average pressure especially in the idle range and part-load range.
It is an object of the present invention to provide a gas valve--in an advantageous embodiment having very short switching and response times and at the same time a large passage cross-section, especially for use in multi-point systems and in supercharged engines, in particular in gas engines for commercial vehicles--which is notable for an opening cross-section which can be simply and rapidly calibrated and adjusted in a certain range.